There was no evidence that the South Korean fisheries official shot and burned by North Korean troops in 2020 intended to defect, South Korea's maritime and military authorities said on Thursday, reversing its earlier announcement.

The official, Lee Dae-jun, went missing at sea in September 2020 while working as a fishing inspector. North Korean authorities later shot him dead and set his body on fire, an incident that shocked many South Koreans and increased cross-border tension.

South Korea's coast guard and military said at the time that Lee appeared to have sought to defect to the North, citing intelligence sources and his gambling debt. But Lee's family refuted the claim, raising a lawsuit calling for the disclosure of government records.

The authorities reversed their earlier announcement on Thursday, saying a reinvestigation determined there was no such evidence.

"We could not find evidence that he had made efforts to cross the border into the North," Park Sang-choon, a coast guard official, told a briefing.

Yoon Hyung-jin, an official at the defence ministry, apologised for "causing confusion" by making an assumption-based announcement.

"As a result of reinvestigation, we could not verify the missing official voluntarily went to the North, but I can clearly say that there was evidence that the North Korean troops shot him dead and burned his body," Yoon said at the same briefing.

Ethan Hee-seok Shin, a legal analyst who works with Lee's family, welcomed the reversal, but said the family sue again, seeking penalties for those who had initially investigated the case and accused Lee of defecting.

"It is a welcome development that the new government is finally moving ... to correct the mean-spirited blame game against the late Lee Dae-jun," Shin told Reuters.

South Korea's new president, Yoon Suk-yeol, met Lee's family before taking office in May and promised to help find the truth.

Yoon's office said it has withdrawn the previous government's appeal for a lower court ruling that allowed the disclosure of some documents owned by the presidential office and coast guard.

North Korea had defended Lee's killing as a "self-defensive measure https://www.reuters.com/article/northkorea-southkorea-idINKBN27F0CH" to head off a coronavirus outbreak, with leader Kim Jong Un making a rare apology days after the incident.